The Lp(a) test is used to identify an elevated level of lipoprotein (a) as a possible risk factor in the development of cardiovascular disease (CVD). The test may be used in conjunction with a routine lipid profile to provide additional information about a person's risk for CVD.
The Lp(a) level is genetically determined and remains relatively constant over an individual's lifetime. Since it is usually not affected by lifestyle changes or by most drugs, it is not the target of therapy. Instead, when Lp(a) is high, the presence of this added risk factor may suggest the need for more aggressive treatment of other, more treatable risk factors such as an elevated low-density lipoprotein (LDL).
Lp(a) is not routinely ordered as part of a lipid profile. However, it may be ordered, along with other lipid tests, when an individual has a strong family history of CVD at a young age that is not explained by high LDL or low HDL.
Some health practitioners may also order these tests when:
A person has existing heart or vascular disease, especially those individuals who have healthy lipid levels or ones that are only mildly elevated
A high Lp(a) level may increase a person's risk for developing CVD and cerebral vascular disease. High Lp(a) can occur in people with a normal lipid profile. An elevated level of Lp(a) is thought to contribute to risk of heart disease independently of other lipids.
The level of Lp(a) is genetically determined and is not easily modified by lifestyle changes or drugs. However, some non-genetic conditions may also lead to elevated Lp(a). These include estrogen depletion, familial hypercholesterolemia, severe hypothyroidism, uncontrolled diabetes, chronic renal failure, and nephrotic syndrome.
There are no known problems associated with low Lp(a). Many individuals have no detectable Lp(a) in their blood.
In rare cases, an Lp(a) level may be ordered when a woman is postmenopausal to see if elevations in Lp(a), tied to decreasing estrogen levels, have significantly increased her risk of developing CVD.
Lp(a) is not a routinely ordered test. A National Cholesterol Education Program (NCEP) guideline, the Adult Treatment Panel III, acknowledged the possible usefulness of Lp(a), but it did not recommend widespread screening. The National Academy of Clinical Biochemistry (NACB) guidelines for emerging biomarkers of CVD and stroke also recommend testing for individuals with a strong family history of premature atheroscleroticheart disease and/or high lipid levels (hyperlipidemia), or those with intermediate cardiovascular risk, but do not recommend general screening.
This is partially due to the fact that Lp(a) levels are genetically determined and difficult to change. Niacin and estrogen (for postmenopausal women) have been shown to lower Lp(a) levels a small amount, but their effect appears to be short-term and it is not known if lowering Lp(a) actually lowers risk. Experts are currently not recommending drug treatments for elevated Lp(a), but some are suggesting that those with elevated Lp(a) should be especially vigilant about lowering their low-density lipoprotein (LDL – the "bad" cholesterol), which may help lower their overall risk.
In general, lipids should not be measured during a fever or major infection, within four weeks of an acute myocardial infarction (heart attack), a stroke, or major surgery, right after excessive alcohol intake, with severely uncontrolled diabetes, when a woman is pregnant, or during rapid weight loss.
This article was last reviewed on July 21, 2014. | This article was last modified on July 21, 2014.
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